The subject of the Michelin Challenge 2017 was to develop a race car that will be competing during Le Mans 24h endurance event in 13 years. Le Mans being the best test for endurance and innovations, the focus during the project was to develop a vehicle that could specifically use its design for the track.
The result of the development is a fully electric race car that could be developed by the manufacturer Tesla. The goal of this project being to bring new feasible technologies onto the racing world in a short term such as 13 years.
Recharging the battery is an issue for endurance racing. The solution developed on this project is to swap the batteries during the pit stop. The battery swap would provide similar time for “refuel” as to a conventional fossil fuel vehicle. Moreover the battery is recharged on the track with regenerative braking, extending the time in between pit stops.
The prototype was designed for efficiency and maximum speed in all conditions. The focus has been on overall aerodynamics of the vehicle with minimum drag for maximum velocity in straight lines and maximum downforce for corners.
To reduce drag, the rear wing was removed, the loss of downforce being compensated by a large Venturi tunnel sucking the prototype to the ground. In order to design the biggest Venturi tunnel possible, the battery pack and driver are located at the smallest area of the tunnel (to the front) which also provides an optimal centre of gravity and weight balance. The diffuser was enlarged by reducing the width of the rear tires.
To further decrease the drag, the rear wheels have a smaller diameter, removing all protruding panels on the upper deck of the prototype.
Reducing the width and diameter of the rear wheels has a large impact on wear and grip. To compensate for the loss, 4 wheels are fitted on the back of the prototype covered by an aerodynamic panel.
The front of the car was designed around the front wings to create maximum downforce at the front and obtain a good balance front / rear. The front rims incorporate a fan design to reduce wheel drag while keeping good cooling for the motors and brakes. Openings in the body provide cooling for the brakes, electric motors, battery pack and driver. The flow is then released at the best location to avoid flow separation around the car; hence the low drag.
The styling of the car was created in collaboration with the engineering and presents fluid lines in alignment with the concept. From the side, the vehicle was visually unbalanced without the rear wing, a vertical tail was introduced bringing a strong visual while also providing space for sponsors.
